This article tries to probe the dispute or polemic that runs through the entire history of humanity, i.e., which is theprimary factor, individual liberty or social interest? Observation of the generative causes of the major viewpoints of Liberalism and Communitarianism leads to this conclusion: in addition to the root cause of the interests of the social strata, there rather exists a difference in epistemology.In ontology,humanity might be the being of the social pursuit of liberty and the social being is generated continuously in the course of liberty pursuit.Should Communitarianism take the generative root of the existence and ideal goal of humanity as the goal itself, and then Liberalism may be considered to tu the goal at the same time into a starting prior root.In order to deepen our understanding and seek solution, we should attribute the foundation to the root cause and the goal to the ideal and try to understand man and its social generation in the tension between the root cause and the ideal.